CN109666131B - Preparation method of polybutylene terephthalate resin - Google Patents
Preparation method of polybutylene terephthalate resin Download PDFInfo
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- CN109666131B CN109666131B CN201710962806.2A CN201710962806A CN109666131B CN 109666131 B CN109666131 B CN 109666131B CN 201710962806 A CN201710962806 A CN 201710962806A CN 109666131 B CN109666131 B CN 109666131B
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- polybutylene terephthalate
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/16—Dicarboxylic acids and dihydroxy compounds
- C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
- C08G63/181—Acids containing aromatic rings
- C08G63/183—Terephthalic acids
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
- C08G63/82—Preparation processes characterised by the catalyst used
- C08G63/85—Germanium, tin, lead, arsenic, antimony, bismuth, titanium, zirconium, hafnium, vanadium, niobium, tantalum, or compounds thereof
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polyesters Or Polycarbonates (AREA)
Abstract
The invention relates to a preparation method of polybutylene terephthalate resin, which mainly solves the problem that in the prior art, the generation of tetrahydrofuran can not be well inhibited by adopting a titanium catalyst in the polymerization process of PBT, so that the generation amount of tetrahydrofuran is high, and the preparation method of the polybutylene terephthalate resin comprises the following steps: carrying out esterification reaction on terephthalic acid and 1, 4-butanediol serving as raw materials by adopting a titanium polyester catalyst to obtain a prepolymer; then carrying out melt polycondensation reaction to obtain a polybutylene terephthalate resin product; the catalyst used was the reaction product of components comprising the following starting materials: 1) titanium compound A: 2) selected from diols B having 2 to 10 carbon atoms; 3) the technical proposal of at least one aliphatic organic acid C selected from organic acids better solves the problem and can be used in the industrial production of polybutylene terephthalate resin.
Description
Technical Field
The invention relates to a preparation method of polybutylene terephthalate resin.
Background
Polybutylene terephthalate (PBT) is thermoplastic polyester formed by Polycondensation of Terephthalic Acid (PTA) or methyl terephthalate and Butanediol (BDO), has the properties of easy processing, good high temperature resistance, moisture resistance, oil resistance and the like, and is widely applied to the fields of automobiles, machinery, instruments, electronics and electrics, household appliances, light spinning, civil use and the like.
The synthesis process of PBT mainly comprises ester exchange method and direct esterification method, and with the appearance of high-purity PTA and the development of direct esterification high-efficiency catalyst, the direct esterification method becomes the main mode of PBT production at present. At present, organic titanate compounds such as tetrabutyl titanate, tetraisopropyl titanate and the like are commonly used as catalysts for PBT synthesis, but the titanate compounds are easy to react with water in a reaction system to decompose and generate solid oxides, so that the catalytic efficiency is reduced; on the other hand, long-term deposition of solid oxides can cause filter clogging, so that heat transfer is hindered, production stoppage and cleaning are caused, and economic loss is caused. In addition, BDO can be dehydrated and cyclized to form Tetrahydrofuran (THF) as a byproduct in the preparation process of PBT, and the formed byproduct not only reduces the reaction efficiency and consumes additional BDO, but also causes the performance of the PBT product to be reduced.
In order to reduce the generation amount of THF as a byproduct and improve the hydrolysis resistance of the PBT catalyst. Patent CN102850534A discloses a TiO prepared by electrostatic spinning method2/SiO2The nanoparticles have been developed to some extent as a catalyst in terms of hydrolysis resistance and THF formation inhibition, but the conditions of the preparation process are severe (high voltage is required), and the solid catalyst is difficult to dissolve in a reaction solution, which affects the catalytic efficiency.
The paper J.of App Poly.Sci Vol 45,371-73(1992) discloses the addition of basic salts in the polymerization process, however the catalyst used is tetrabutyl titanate, which still presents hydrolysis problems.
Patent CN1720216A discloses a catalyst composition comprising the reaction product of an alkoxide or condensed alkoxide of a metal M selected from titanium, zirconium, hafnium, aluminium or the lanthanide series, an alcohol containing at least two hydroxyl groups, a 2-hydroxycarboxylic acid and a base. In this patent, the hydrolysis resistance of the catalyst is improved to some extent, but no correlation with the inhibition of THF formation is reported. And we have found that the preferred ratios of acid, base and metal M in the examples of this patent are not effective in reducing THF formation.
Disclosure of Invention
The invention aims to solve the technical problem that the generation of tetrahydrofuran can not be well inhibited by adopting a titanium catalyst in the traditional PBT polymerization process, so that the generation amount of the tetrahydrofuran is high, and provides a novel preparation method of polybutylene terephthalate resin. The method can better inhibit the generation of the reproduced tetrahydrofuran, and has the advantage of lower generation amount of the tetrahydrofuran reaction.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a method for preparing polybutylene terephthalate resin comprises the following steps:
a) carrying out esterification reaction on terephthalic acid and 1, 4-butanediol serving as raw materials by adopting a titanium polyester catalyst to obtain a prepolymer; then carrying out melt polycondensation reaction to obtain a polybutylene terephthalate resin product; the catalyst used was a reaction product comprising the following starting materials:
(1) titanium compound a having the general formula:
Ti(OR)4
r is selected from straight-chain or branched alkyl with 1-10 carbon atoms;
(2) selected from diols B having 2 to 10 carbon atoms;
(3) at least one aliphatic organic acid C selected from organic acids;
wherein the molar ratio of the glycol B to the titanium compound A is (1-8) to 1; the molar ratio of the aliphatic organic acid C to the titanium compound A is (0.1-20) to 1.
In the above technical solution, the terephthalic acid is preferably purified terephthalic acid.
In the above technical solution, the titanium compound a preferably has a general formula shown in formula (I):
wherein R is1To R4Is independently selected from C1～C8A hydrocarbon group of (1). By way of example, the titanium compound a may be, for example, at least one selected from the group consisting of tetramethyl titanate, tetraethyl titanate, tetraethylhexyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, and tetraisooctyl titanate.
In the above technical solution, the diol B is preferably at least one selected from the group consisting of 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, ethylene glycol, 1, 6-hexanediol, 1, 4-cyclohexanedimethanol, and diethylene glycol.
In the above technical solution, the aliphatic organic acid C is preferably at least one selected from lactic acid, citric acid, malic acid, tartaric acid and oxalic acid.
In the technical scheme, the weight of titanium atoms is 10-160 ppmw based on the weight of polyester products obtained by melt polycondensation.
In the technical scheme, the molar ratio of the glycol B to the titanium compound A is preferably (1-4) to 1; the molar ratio of the aliphatic organic acid C to the titanium compound A is preferably (0.1-15) to 1.
In the technical scheme, the reaction temperature of the esterification reaction is preferably 230-280 ℃, and the reaction pressure is preferably normal pressure-0.5 MPa.
In the technical scheme, the reaction temperature of the melt polycondensation reaction is preferably 250-320 ℃, and the reaction pressure is preferably less than 150 Pa.
In the technical scheme, the intrinsic viscosity of the polybutylene terephthalate resin product is more than 1.0 deciliter/gram.
In the technical scheme, the used catalyst is preferably a reaction product obtained by reacting the following raw materials at 0-200 ℃ for 0.5-10 hours:
(1) titanium compound a having the general formula:
Ti(OR)4
r is selected from straight-chain or branched alkyl with 1-10 carbon atoms;
(2) selected from diols B having 2 to 10 carbon atoms;
(3) at least one aliphatic organic acid C selected from organic acids.
In the above technical solution, the aliphatic organic acid C is preferably two or more selected from lactic acid, citric acid, malic acid, tartaric acid or oxalic acid, and at this time, the two aliphatic organic acids have a synergistic effect, so that the amount of tetrahydrofuran produced can be further reduced.
In the technical scheme, the preferable range of the reaction temperature for preparing the polyester catalyst is 10-180 ℃, and the preferable range of the reaction time is 2-6 hours.
The preparation method of the titanium polyester catalyst comprises the following steps:
adding a titanium compound A into a required amount of dihydric alcohol B for reaction to obtain a reaction product; and then adding the reaction product into butanediol, and adding aliphatic organic acid C to react to obtain the homogeneous liquid titanium polyester catalyst.
The preparation method of the polyester comprises the following steps:
the method can adopt a known polyester preparation method, and comprises the first step of carrying out esterification reaction on purified terephthalic acid and 1, 4-butanediol to obtain a prepolymer, wherein the reaction temperature is 200-230 ℃, the reaction pressure is normal pressure, the esterification reaction is carried out to obtain the prepolymer, and then the reaction temperature is 230-250 ℃, and the reaction pressure is less than 150 Pa. The titanium polyester catalyst is added into the reaction system before the esterification reaction is started. And cutting and storing after the reaction is finished.
In the present invention, the intrinsic viscosity, hue, etc. of the polyester are measured by the following methods:
(1) intrinsic viscosity: the phenol-tetrachloroethane mixture is used as a solvent, and is measured by an Ubbelohde viscometer at the temperature of 25 ℃.
(2) Hue: the pellet samples were treated at 135 ℃ for 1 hour and measured for Hunter L value (lightness), a value (red-green hue) and b value (yellow-blue hue) using a color-view automatic color difference meter from BYK Gardner. Wherein, the higher the L value, the larger the brightness; when the value of b is high, the polyester chip is yellowish. For the present invention, a high L value and a low b value are desired.
The inventor surprisingly discovers that the catalyst adopts the three components, and compared with the PBT polyester prepared by tetrabutyl titanate, the PBT polyester prepared by the method has the advantages of lower generation amount of tetrahydrofuran, higher reaction speed and better technical effect.
The invention is further illustrated by the following examples.
Detailed Description
[ example 1 ]
Preparation of catalyst A
In a reactor equipped with a stirrer, a condenser and a thermometer, 12.4 g (0.2 mol) of ethylene glycol was added, 28.4 g (0.1 mol) of tetraisopropyl titanate was slowly dropped into the reactor to precipitate a white precipitate, the reaction was carried out at 70 ℃ for 2 hours, the product was centrifuged, and the residue was washed with distilled water 3 times, and the product was vacuum-dried at 70 ℃ to obtain a white powdery substance.
The dried white powdery material was placed in a reactor equipped with a stirrer, a condenser and a thermometer, and 90 g of 1, 4-butanediol and 126 g (0.6 mol) of citric acid monohydrate were added and reacted at a reaction temperature of 150 ℃ for 2 hours to obtain a nearly colorless homogeneous liquid as catalyst A.
Preparation of polyesters
Mixing 600 g of terephthalic acid, 520 g of 1, 4-butanediol and a catalyst A (based on the amount of the generated polyester, the weight of titanium atoms is 70ppmw) to prepare a slurry, adding the slurry into a polymerization kettle for esterification reaction, wherein the esterification temperature is 200-225 ℃, the pressure is normal pressure, and discharging water and tetrahydrofuran generated in the reaction through a rectifying device. After the esterification is finished, vacuumizing and reducing the pressure until the system pressure is lower than 100Pa, gradually increasing the reaction temperature to 250 ℃, stopping the reaction when the stirring power meets the requirement, continuously extruding the reaction product from the bottom of the polymerization kettle in a strip shape, cooling and pelletizing.
The test results are shown in Table 1.
[ example 2 ]
Polyester production was carried out in the same manner as in example 1 except that the amount of the catalyst A (the weight of titanium atoms was changed to 60ppmw based on the amount of the polyester produced) was changed.
The test results are shown in Table 1.
[ example 3 ]
Polyester production was carried out in the same manner as in example 1 except that the amount of the catalyst A (based on the amount of the polyester produced, the weight of titanium atoms was changed to 80 ppmw).
The test results are shown in Table 1.
[ example 4 ]
Polyester production was carried out in the same manner as in example 1 except that the weight of titanium atoms was changed to 120ppmw based on the amount of polyester produced as catalyst A).
The test results are shown in Table 1.
[ example 5 ]
Preparation of catalyst B
In a reactor equipped with a stirrer, a condenser and a thermometer, 12.4 g (0.2 mol) of ethylene glycol was added, 28.4 g (0.1 mol) of tetraisopropyl titanate was slowly dropped into the reactor to precipitate a white precipitate, the reaction was carried out at 70 ℃ for 2 hours, the product was centrifuged, and the residue was washed with distilled water 3 times, and the product was vacuum-dried at 70 ℃ to obtain a white powdery substance.
The dried white powdery substance was put into a reactor equipped with a stirrer, a condenser and a thermometer, and 90 g of 1, 4-butanediol and 54 g (0.6 mol) of lactic acid were added thereto, and reacted at a reaction temperature of 150 ℃ for 2 hours to obtain a nearly colorless homogeneous liquid as a catalyst B.
The polyester was produced in the same manner as in example 1.
The test results are shown in Table 1.
[ example 6 ]
Polyester production was carried out in the same manner as in example 1 except that the amount of lactic acid in example 5 was changed to 90 g (1 mol).
The test results are shown in Table 1.
[ example 7 ]
Preparation of catalyst C
In a reactor equipped with a stirrer, a condenser and a thermometer, 12.4 g (0.2 mol) of ethylene glycol was added, 28.4 g (0.1 mol) of tetraisopropyl titanate was slowly dropped into the reactor to precipitate a white precipitate, the reaction was carried out at 70 ℃ for 2 hours, the product was centrifuged, and the residue was washed with distilled water 3 times, and the product was vacuum-dried at 70 ℃ to obtain a white powdery substance.
The dried white powdery material was placed in a reactor equipped with a stirrer, a condenser and a thermometer, and 90 g of 1, 4-butanediol, 63 g (0.3 mol) of citric acid monohydrate and 27 g (0.3 mol) of lactic acid were added and reacted at a reaction temperature of 150 ℃ for 2 hours to obtain a nearly colorless homogeneous liquid as catalyst C.
The polyester was produced in the same manner as in example 1.
The test results are shown in Table 1.
、
[ COMPARATIVE EXAMPLE 1 ]
Polyester production was carried out in the same manner as in example 1 except that in example 1, the catalyst A was changed to tetrabutyl titanate (the weight of titanium atoms was 90ppmw based on the amount of polyester produced).
The test results are shown in Table 1.
TABLE 1
Claims (8)
1. A method for preparing polybutylene terephthalate resin comprises the following steps:
carrying out esterification reaction on terephthalic acid and 1, 4-butanediol serving as raw materials by adopting a titanium polyester catalyst to obtain a prepolymer; then carrying out melt polycondensation reaction to obtain a polybutylene terephthalate resin product; the titanium polyester catalyst is a reaction product obtained by reacting the following raw materials at 0-200 ℃ for 0.5-10 hours:
(1) titanium compound a having the general formula:
Ti(OR)4
r is selected from straight-chain or branched alkyl with 1-10 carbon atoms;
(2) ethylene glycol;
(3) at least one aliphatic organic acid C selected from organic acids;
wherein the molar ratio of the ethylene glycol to the titanium compound A is (1-8) to 1; the molar ratio of the aliphatic organic acid C to the titanium compound A is (0.1-20) to 1;
the aliphatic organic acid C is at least one of lactic acid, citric acid, malic acid, tartaric acid or oxalic acid,
the preparation method of the titanium polyester catalyst comprises the following steps: adding a titanium compound A into ethylene glycol with required amount for reaction to obtain a reaction product; and then adding the reaction product into butanediol, and adding aliphatic organic acid C to react to obtain the homogeneous liquid titanium polyester catalyst.
2. The method for preparing polybutylene terephthalate resin according to claim 1, wherein the titanium compound a has a general formula represented by formula (I):
wherein R is1To R4Is independently selected from C1～C8A hydrocarbon group of (1).
3. The method of preparing polybutylene terephthalate resin according to claim 1, wherein the catalyst is miscible with water and 1, 4-butanediol.
4. The process for producing a polybutylene terephthalate resin according to claim 1, wherein the weight of titanium atoms is 10 to 160ppmw based on the amount of the polyester formed.
5. The method of preparing polybutylene terephthalate resin according to claim 1, wherein the esterification reaction is carried out at a reaction temperature of 230 to 280 ℃ and a reaction pressure of normal pressure to 0.5 MPa.
6. The method of preparing polybutylene terephthalate resin according to claim 1, wherein the melt polycondensation reaction is carried out at a reaction temperature of 250 to 320 ℃ and a reaction pressure of less than 150 Pa.
7. The process for producing a polybutylene terephthalate resin according to claim 1, wherein the intrinsic viscosity of the polybutylene terephthalate resin product is more than 1.0 dl/g.
8. The method for producing a polybutylene terephthalate resin according to any one of claims 1 to 7, wherein the aliphatic organic acid C is two or more selected from lactic acid, citric acid, malic acid, tartaric acid, and oxalic acid.
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| CN112679463B (en) * | 2019-10-17 | 2022-11-01 | 中国石油化工股份有限公司 | Method for preparing glycolide by using waste polyglycolic acid and application of titanium catalyst in polyglycolic acid depolymerization |
| CN114075238B (en) * | 2020-08-19 | 2023-11-17 | 中国石油化工股份有限公司 | Preparation method of tetrabutyl glycol titanate |
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